Comments have come in as to where and when to obtain the No Objection Statement for a J-1 waiver regardless of whether the funding comes from the home country or the U.S. All No Objection Statements must be obtained from the Embassy of the home country located in Washington DC. The actual statement should be forwarded to the Dept. of State AFTER you have submitted your J-1 waiver application on line and have a case number. The statement should include your case number so that it ends up in the right file. When you file the waiver you will have an address where to send all supporting documents. Give that to your Embassy as well so that they send the statement to the right Dept. of State office.
Your request for a No Objection Statement should be carefully drafted and offer persuasive reasons AND evidence why you should be issued the Statement.
As for timing, make sure that you file your waiver after your last extension. Once you file the waiver you will have indicated to the U.S. government your intent to want to remain in the U.S. This intent is incompatible with J-1 intent.